Answer
$(n-5)^2$
Work Step by Step
The given expression, $
-10n+25+n^2
,$ is equivalent to
\begin{align*}
&
n^2-10n+25
\\&=
(n)^2-2(5n)+(5)^2
\\&=
(n)^2-2(n\cdot5)+(5)^2
.\end{align*}
Using $(x+y)^2=(x)^2+2(x\cdot y)+(y)^2$ or the square of a binomial, the expression above is equivalent to
\begin{align*}
(n-5)^2
.\end{align*}
